Uncooled semiconductor lasers of various types are used in a variety of digital lightwave communications systems primarily due to their cost effectiveness. One example is the capped mesa buried heterostructure (CMBH) distributed feedback (DFB) laser. While such lasers are generally effective, the devices can exhibit eye closure and bit error rate problems when operated at low bias (typically less than 3 milliamps) necessitated when operated at low temperature (typically less than -20 degrees C.). This problem, is also known as the low bias capacitance effect.
It is, therefore, desirable to reduce the adverse effects of low temperature and low bias in uncooled lasers.